<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script type="text/javascript">
		var str="Hello world!"
		document.write(str.indexOf("Hello") + "<br />")
		document.write(str.indexOf("World") + "<br />")
		document.write(str.indexOf("world"))
		</script>
		<script type="text/javascript">
		var str="Hello world!"
		document.write(str.substr(3))
		
		</script>
		<script type="text/javascript">
		
		var str="Hello world!"
		document.write(str.substring(3,6))
		
		</script>
	</body>
</html>
